Abstract

Coherent terahertz pulses have been generated at by frequency-mixing two laser lines near based on collinearly phase-matched difference-frequency generation in GaSe crystals. The highest average output power was measured to be , corresponding to a peak output power of . Both the average powers and normalized conversion efficiencies have been significantly improved over the previous results. The generated terahertz pulses are expected to have the narrowest linewidth dictated by the pulse width through Fourier transform based on the characteristics of the two laser beams.